I. Field of the Invention
The present invention relates to mining equipment and more particularly to a device for changing bore crowns on a drill rod.
II. Description of the Prior Art
In short hole drilling, which is carried out with the aid of a single or multiple jib drilling jumbo rig, the present inconvenience is that the drill operator is repeatedly compelled to move away from the control center to replace dulled drill rods. At present, as the drilling is mostly with but few exceptions done with fixed rods, the rod has to be changed on the average after every fourth drilled hole. In order to complete a whole blasting front e.g. with a three-jib jumbo, the rod has to be changed from 15 to 20 times during a period of about 2 hours, that is approximately every six minutes. Such manual drill rod replacement has several drawbacks. On the one hand it slows down the drilling operation because the other machines may be idle while the operator is away changing a rod and on the other hand there are considerations of work safety; it is highly dangerous to work close to the rotating rods, particularly if the ground is slippery and uneven and the visibility is poor. The heavy weight of the rods makes this a strenuous manual work phase. The drill operator is furthermore bothered by oil mist and noise. The last-mentioned detriments would be eliminated if the drill operator could stay in the insulated cab. This would require, however, that the drill operator need not leave his shelter when a rod has dulled and that instead the replacement could be effected by a remote control.